Contra-angle dental hand piece



Nov. 2l, 1939. H, H BEARDSLEY 2,180,499

' CONTRA-ANGLE DENTAL HAND PIECE Filed 001;.' 3., 1938 el e Patented Nov. 21, 1939 UNITED STATES PATENT #OFFICE CONTRA-ANGLE DENTALHAND yPIECE Harold H. Beardsley, Denver, Colo.

Application October 3,

6 Claims.

This invention relates to improvement in dental contra-angle hand pieces and particularly to improvement in burr-receiving, retaining and 4releasing means in such hand pieces.

' Objects of this invention are to provide, in such .a device, (a.) an improved chuck, (b) improved means for retaining the burr shank in exact axial alignment and eliminating vibration during rotation, (c) improved means for opening the chuck for removal of the burr shank or for admission of the burr shank thereintoand for clamping the burr shank in operative position, and (d) providing a rotating clamping means having a smooth, non-rotatable exterior.

In my pendingapplication, Serial No. 139,132 illed April 2.7, 1937, I have disclosed lever reciprocation of rotatable means for clamping the chuck upon the burr shank. Objects of the present invention are modifications, variations and improvements of the structure there disclosed.

With these and other objects in view, as will hereinafter more fully appear, my invention comprises certain novelconstructions, combinations and arrangements of parts as described inthe following speciiication and defined in the appended claims and illustrated in the accompanying.

drawing in which Fig. 1 is a side elevation of a complete contra-angle hand piece constructed according to my invention.

Fig. 2 is an enlarged fragment of Fig. l partly in elevation but mostly in central section, illustrating the device with the burr clamped in -po sition for operation.

Fig. 3 is a sectional View on line 3-3 of Fig. -2 looking in the direction of the arrowsbut not including the burr and showing the clamping mechanism in released or open position.

Fig. 4 is a fragmentary View on line 4-'4 of Fig. 2 looking in the direction of the arrows.

Fig. 5 is a. section on line 5-5 of Fig. 3.

Fig. 6 is a section on line 6-6 of Fig. 2.

Fig. 7 is a fragmentary sectional view of a modification of the mounting of the pin fulcrum of the lever.

As in the disclosure inmy pending application, above referred to, I use a handle and operating means enclosed therein of the type now in common use, the same being indicated generally .at H, .which handle carries a member I which, in turn, carries head housing 2, conveniently formed integrally as illustrated.

Within member I is the usual operating shaft carrying suitable gear 4 which meshes with a gear 5 carried by hub 6, having shoulder I seated 1938, Serial N0. 232,947

on a suitablebearing within housing `2 such as y the upper or inner end `of sleeve 8 which is threaded into 'housing 2 and is provided with an annular ring 9 which limits the movement of sleeve 8 into housing 2. Sleeve 8' has a downwardly extending portion 8a which extends the bearing for hub 6 and also serves otherpurposes as hereinafter described.

Hub 6 carries an axially positioned chuck Ill suitably affixed therein as by dovetailing 6a and having an axial bore II for accommodation of a burr shank I2, the lower or outer end of chuck I0 being slit as at I3 to form fingers I4. v The shank clamping means, hereinafter described, when accurately constructed,` will sol tightly hold the shank as to causeI the shank to rotate with the chuck but to insuref such coincident rotation and prevent slipping, even in case of inaccurate construction, positive means may be provided such as cut out I5 in the shank and comating projecting I6 on the inner wall of the chuck.` .l o.

The upper or inner end of the shank'l2 projects into a recess I'I inthe top of housing 2 and near this end the shank is annularly grooved as at I8 for the reception of the inner edges of slide I9 adapted by projection into said'l groove I8 to prevent accidental.'longitudinal displacement of the shank I2 while fitting sufficiently loosely in said groove I8 to permit free rotation of the shank without substantial frictional contact `with.y slide I9. The housing 2 is'slotted as at 2Iljto accommodate slide I9 with a suitable sliding iit. Slide I9 is provided with suitable means as lugs 2I for engagement by the lever for operation' of the slide as hereinafter described. l

It will be understood that the 'shank I2 has a nice sliding fit within bore II ,so that a very slight contraction of fingers I4 will tightly grip shank I2. `The fingers I4 project a substantial distance from hub 6 as clearlyv shown at Figs. 2 and 3. Ring 22, split as at 23, has a normal interior circumference slightly less than the outer` circumference of fingers I4 when clamped against shank I2.` Suitable provision is `made for permitting ring 22 tobe `forced over the'ends of fingers I4 as by bevelling or rounding the outer edges of the ends of lingers I4 as at I4a.

Ring 22is positioned within the'bottom of a cup 24 and is retained thereby bythe foot of Ly sleeve 25 tightly fitting within the walls of cup 24 and forming a sleeve bearing for said cup on the sleeve 8a whereby the cup andsleeve may be slid, longitudinally on said sleeve 8a, upwardly until the rim of the cup and sleeve seat. against 

